Installation of St. Lawrence River Ice Booms

This information was provided by Ontario Power Generation (OPG) on November 26, 2025.

Notice to River Users

Cornwall – Ontario Power Generation (OPG) is advising water users on the St. Lawrence River that ice booms will be installed in narrow stretches of the river. The work begins on Monday, December 1, 2025, and will continue through the remainder of the year.

Ice booms are chain and wood devices used to promote the formation of a smooth sheet of ice on the river. The smooth sheet helps to mitigate ice flow and ice jamming during winter months. The booms are placed in the river off Galop Island, in the North Channel, near Johnstown and at Prescott.

The annual installation of ice booms takes place in the same narrow reaches of the St. Lawrence River every fall. They are removed in the spring once the ice has melted, and ahead of the St. Lawrence Seaway shipping season.

All users of the river should take extra caution in the narrow reaches where the boom installation work is being performed.

OPG would also like to remind all users of the river to take every precaution around dams and generating stations. To learn more about water safety, please visit opg.com/watersafety.

About OPG

As Ontario’s largest and one of North America’s most diverse electricity generators, OPG invests in local economies and employs thousands of people across Ontario. Learn more about how OPG and its family of companies are advancing the development of new low-carbon technologies, refurbishment projects, and electrification initiatives to power the growing demands of a clean economy at OPG.com.

For further information, please contact:
Ontario Power Generation
416-592-4008 or 1-877-592-4008
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